In Galatians 4:9, why does Paul say ‘But now knowing God, or rather being known by God’?

This text is from a letter written by David Gooding in 1994.

When Paul says in Galatians 4:9 'But now knowing God, or rather being known by God', he is making a very important distinction.

I can, for instance, know a lot about the president of the United States, while the president himself does not know me or anything about me. It is, therefore, right to speak of our coming to know God through Jesus Christ; but it is even more important to be aware of the fact that God knows us, and by his gracious initiative has entered into a personal relationship with us.

So I repeat, while it is very good and proper to talk of our knowing God, it is even more important to realize that God knows us; and that in this process he himself, and not we, took the initiative.

Yours very sincerely,